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![Uwe Kleine-König](/assets/img/avatar_default.png)
.get_state() might fail in some cases. To make it possible that a driver signals such a failure change the prototype of .get_state() to return an error code. This patch was created using coccinelle and the following semantic patch: @p1@ identifier getstatefunc; identifier driver; @@ struct pwm_ops driver = { ..., .get_state = getstatefunc ,... }; @p2@ identifier p1.getstatefunc; identifier chip, pwm, state; @@ -void +int getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { ... - return; + return 0; ... } plus the actual change of the prototype in include/linux/pwm.h (plus some manual fixing of indentions and empty lines). So for now all drivers return success unconditionally. They are adapted in the following patches to make the changes easier reviewable. Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com> Acked-by: Douglas Anderson <dianders@chromium.org> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20221130152148.2769768-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
236 lines
6 KiB
C
236 lines
6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Intel Keem Bay PWM driver
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*
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* Copyright (C) 2020 Intel Corporation
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* Authors: Lai Poey Seng <poey.seng.lai@intel.com>
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* Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
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*
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* Limitations:
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* - Upon disabling a channel, the currently running
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* period will not be completed. However, upon
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* reconfiguration of the duty cycle/period, the
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* currently running period will be completed first.
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*/
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#include <linux/bitfield.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/regmap.h>
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#define KMB_TOTAL_PWM_CHANNELS 6
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#define KMB_PWM_COUNT_MAX U16_MAX
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#define KMB_PWM_EN_BIT BIT(31)
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/* Mask */
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#define KMB_PWM_HIGH_MASK GENMASK(31, 16)
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#define KMB_PWM_LOW_MASK GENMASK(15, 0)
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#define KMB_PWM_LEADIN_MASK GENMASK(30, 0)
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/* PWM Register offset */
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#define KMB_PWM_LEADIN_OFFSET(ch) (0x00 + 4 * (ch))
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#define KMB_PWM_HIGHLOW_OFFSET(ch) (0x20 + 4 * (ch))
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struct keembay_pwm {
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struct pwm_chip chip;
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struct device *dev;
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struct clk *clk;
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void __iomem *base;
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};
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static inline struct keembay_pwm *to_keembay_pwm_dev(struct pwm_chip *chip)
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{
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return container_of(chip, struct keembay_pwm, chip);
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}
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static void keembay_clk_unprepare(void *data)
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{
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clk_disable_unprepare(data);
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}
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static int keembay_clk_enable(struct device *dev, struct clk *clk)
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{
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int ret;
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ret = clk_prepare_enable(clk);
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if (ret)
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return ret;
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return devm_add_action_or_reset(dev, keembay_clk_unprepare, clk);
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}
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/*
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* With gcc 10, CONFIG_CC_OPTIMIZE_FOR_SIZE and only "inline" instead of
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* "__always_inline" this fails to compile because the compiler doesn't notice
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* for all valid masks (e.g. KMB_PWM_LEADIN_MASK) that they are ok.
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*/
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static __always_inline void keembay_pwm_update_bits(struct keembay_pwm *priv, u32 mask,
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u32 val, u32 offset)
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{
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u32 buff = readl(priv->base + offset);
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buff = u32_replace_bits(buff, val, mask);
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writel(buff, priv->base + offset);
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}
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static void keembay_pwm_enable(struct keembay_pwm *priv, int ch)
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{
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keembay_pwm_update_bits(priv, KMB_PWM_EN_BIT, 1,
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KMB_PWM_LEADIN_OFFSET(ch));
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}
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static void keembay_pwm_disable(struct keembay_pwm *priv, int ch)
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{
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keembay_pwm_update_bits(priv, KMB_PWM_EN_BIT, 0,
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KMB_PWM_LEADIN_OFFSET(ch));
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}
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static int keembay_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
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struct pwm_state *state)
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{
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struct keembay_pwm *priv = to_keembay_pwm_dev(chip);
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unsigned long long high, low;
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unsigned long clk_rate;
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u32 highlow;
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clk_rate = clk_get_rate(priv->clk);
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/* Read channel enabled status */
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highlow = readl(priv->base + KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));
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if (highlow & KMB_PWM_EN_BIT)
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state->enabled = true;
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else
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state->enabled = false;
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/* Read period and duty cycle */
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highlow = readl(priv->base + KMB_PWM_HIGHLOW_OFFSET(pwm->hwpwm));
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low = FIELD_GET(KMB_PWM_LOW_MASK, highlow) * NSEC_PER_SEC;
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high = FIELD_GET(KMB_PWM_HIGH_MASK, highlow) * NSEC_PER_SEC;
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state->duty_cycle = DIV_ROUND_UP_ULL(high, clk_rate);
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state->period = DIV_ROUND_UP_ULL(high + low, clk_rate);
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state->polarity = PWM_POLARITY_NORMAL;
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return 0;
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}
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static int keembay_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
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const struct pwm_state *state)
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{
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struct keembay_pwm *priv = to_keembay_pwm_dev(chip);
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struct pwm_state current_state;
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unsigned long long div;
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unsigned long clk_rate;
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u32 pwm_count = 0;
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u16 high, low;
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if (state->polarity != PWM_POLARITY_NORMAL)
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return -EINVAL;
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/*
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* Configure the pwm repeat count as infinite at (15:0) and leadin
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* low time as 0 at (30:16), which is in terms of clock cycles.
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*/
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keembay_pwm_update_bits(priv, KMB_PWM_LEADIN_MASK, 0,
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KMB_PWM_LEADIN_OFFSET(pwm->hwpwm));
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keembay_pwm_get_state(chip, pwm, ¤t_state);
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if (!state->enabled) {
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if (current_state.enabled)
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keembay_pwm_disable(priv, pwm->hwpwm);
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return 0;
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}
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/*
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* The upper 16 bits and lower 16 bits of the KMB_PWM_HIGHLOW_OFFSET
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* register contain the high time and low time of waveform accordingly.
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* All the values are in terms of clock cycles.
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*/
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clk_rate = clk_get_rate(priv->clk);
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div = clk_rate * state->duty_cycle;
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div = DIV_ROUND_DOWN_ULL(div, NSEC_PER_SEC);
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if (div > KMB_PWM_COUNT_MAX)
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return -ERANGE;
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high = div;
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div = clk_rate * state->period;
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div = DIV_ROUND_DOWN_ULL(div, NSEC_PER_SEC);
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div = div - high;
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if (div > KMB_PWM_COUNT_MAX)
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return -ERANGE;
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low = div;
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pwm_count = FIELD_PREP(KMB_PWM_HIGH_MASK, high) |
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FIELD_PREP(KMB_PWM_LOW_MASK, low);
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writel(pwm_count, priv->base + KMB_PWM_HIGHLOW_OFFSET(pwm->hwpwm));
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if (state->enabled && !current_state.enabled)
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keembay_pwm_enable(priv, pwm->hwpwm);
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return 0;
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}
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static const struct pwm_ops keembay_pwm_ops = {
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.owner = THIS_MODULE,
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.apply = keembay_pwm_apply,
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.get_state = keembay_pwm_get_state,
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};
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static int keembay_pwm_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct keembay_pwm *priv;
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int ret;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(priv->clk))
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return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clock\n");
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priv->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(priv->base))
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return PTR_ERR(priv->base);
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ret = keembay_clk_enable(dev, priv->clk);
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if (ret)
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return ret;
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priv->chip.dev = dev;
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priv->chip.ops = &keembay_pwm_ops;
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priv->chip.npwm = KMB_TOTAL_PWM_CHANNELS;
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ret = devm_pwmchip_add(dev, &priv->chip);
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if (ret)
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return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
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return 0;
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}
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static const struct of_device_id keembay_pwm_of_match[] = {
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{ .compatible = "intel,keembay-pwm" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, keembay_pwm_of_match);
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static struct platform_driver keembay_pwm_driver = {
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.probe = keembay_pwm_probe,
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.driver = {
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.name = "pwm-keembay",
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.of_match_table = keembay_pwm_of_match,
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},
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};
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module_platform_driver(keembay_pwm_driver);
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MODULE_ALIAS("platform:pwm-keembay");
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MODULE_DESCRIPTION("Intel Keem Bay PWM driver");
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MODULE_LICENSE("GPL v2");
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